1. Field of the Invention
This invention relates, in general, to air conditioning systems. In particular, the invention relates to a system in which conditioned air is supplied to a plurality of rooms from one air conditioning apparatus through a duct.
2. Description of the Related Art
In a conventional air conditioning system including one air conditioning apparatus and a common duct which communicates with a plurality of rooms to be air-conditioned, a plurality of paths are provided between the common duct and the plurality of rooms. An automatic air volume control device, i.e., a so-called VAV (variable air volume) device, usually is provided in each path. In such an automatic air control device (hereinafter referred to as a VAV device) includes a damper and an air volume sensor to control an amount of heated/cooled air flowing into the corresponding room through the damper. The opening degree of the damper is controlled on the basis of the air conditioning load of the corresponding room. The air conditioning load is a difference between a desired room temperature set through a room thermostat provided in each room and a detected room temperature.
In the above-described conventional air conditioning system including the VAV device, ON/OFF operations of both the air conditioning apparatus and the VAV device are executed independently. The air conditioning apparatus may operate while dampers of VAV devices are closed. The compressor and the fan device of the air conditioning apparatus operate at a prescribed low rotational speed respectively when the air conditioning apparatus operates. Thus, electric energy may be consumed uselessly until the VAV device operates. Furthermore, the temperature of the conditioned air fed from the air conditioning apparatus is previously set at a desirable value through the operation panel of the air conditioning apparatus irrespective of actual heat load in each room to be air-conditioned. Thus, insufficient air-conditioning to each room may occur when the desired room temperature set through the room thermostat in each room is excessively high or low, as compared with the actual room temperature, in other words, when the heat load in each room is excessively large.